Device including means for setting a first rotatable member relative to a second rotatable member

ABSTRACT

A first annular member keyed to a shaft is provided internally with regularly spaced axial grooves, and a second annular member concentric with the shaft is provided internally with regularly spaced axial grooves. The angular positions of the individual annular members are determined and their resulting relative angular setting accurately effected by arranging a ridge on the circumference of a sleeve to engage aligned grooves on the first and second annular members. The number of grooves on the first and second annular members differs to give a Vernier effect. One the sleeve effects the setting, the shaft and the second annular member are coupled to be rotatable relative to a common reference point.

United States Patent [72] Inventor Eric John Elliott 2,560,850 7/1951Day 74/527 St. Albans, England 2,612,051 9/1952 Felt 74/527 [21] Appl.No. 1,756 2,665,489 1/1954 Cunningham 33/164 [22] Filed Jan. 9, 19702,680,992 6/1954 Herbain 33/164 [45] Patented Aug. 24, 1971 3,091,8666/1963 Kachergis 33/164 [73] Assignee English Numbering Machines Limited3,386,312 6/1968 Weasler 74/527 32 Fri g Primary Examiner-Milton Kaufmani omy Assistant ExaminerWesley S. Ratliff, Jr. 4% 9 Attorney-Nolte andNolte [54] DEVICE INCLUDING MEANS FOR SE'I'IING'A FIRST ROTATABLE MEMBERRELATIVE TO A SECQND ROTATABITE MEMBER ABSTRACT: A first annular memberkeyed to a shaft is pro- 2 Claims, 4 Drawing Figs.

vrded internally with regularly spaced axial grooves, and a U.S. econdannular member concentric the shaft is provided 74/8915, 33/164 Rinternally with regularly spaced axial grooves. The angular llpositionsof the individual annular members are determined. F16h 27/02 and theirresulting relative angular setting accurately effected Fleld of Searchby arranging a on the circumference of a leeve to en- 33/164 gagealigned grooves on the first and second annular members. The number ofgrooves on the first and second annular [56]. Rem'enm cued membersdiffers to give a Vernier effect. One the sleeve ef- UNXTED STATESPATENTS fects the setting, the shaft and the second annular member are1,385,405 7/1921 Tangen 33/ 164 coupled to be rotatable relative to acommon reference point.

77-- Va /4 a 75 I I A 20 PATENTEI] ausemsn INVENTOR ERIC JOHN ELLIOTTW/AZJ Mi ATTORNEYS DEVICE INCLUDING MEANS FOR SETTING A FIRST ROTATABLEMEMBER RELATIVE TO A SECOND ROTATABLE MEMBER BACKGROUND TO THE INVENTIONThis invention relates to a device including means for setting a firstrotatable member relative to a second rotatable member.

An example of such a device is a micrometer, where it is necessary toensure that the zero setting of the micrometer spindle corresponds to azero reading on the micrometer measuring or counter unit. Hitherto,difficult adjustments have been required in some cases necessitatingfurther machine work being carried out to bring components into accuratealignment.

SUMMARY OF THE INVENTION According to one feature of the invention thereis provided a device including means for setting a first rotatablemember relative to a second rotatable member comprising, a shaftproviding said first rotatable member, a first annular member having afirst axially extending bore and rotatable with said shaft, at least aportion of the first axially extending bore being of such diameterrelative to the diameter of the shaft adjacent thereto to allow aclearance between the shaft and the first annular member along saidportion of the bore, a first plurality of grooves regularly spacedaround the periphery of said bore portion, a second annular memberhaving a second axially extending bore providing said second rotatablemember and arranged to be coaxial with said shaft, the diameter of saidsecond axially extending bore allowing clearance along the entire lengthof said second bore between the second annular member and the shaft, asecond plurality of grooves different in number from said firstplurality of grooves being regularly spaced around the periphery of saidsecond bore, a sleeve fitting and displaceable along said shaft, a ridgeon the outer periphery said sleeve engageable with aligned ones of saidfirst and second plurality of grooves, whereby the relative angularsetting of the second rotatable member relative to the first rotatablemember may be effected by aligning first groove in the first annularmember with a second groove in the second annular member and locatingthe ridge of said sleeve member in said aligned grooves.

Preferably, the ridge on said sleeve is formed by a resilient stripextending from the wall of the sleeve whereby the ridge is located inthe aligned first and second grooves by rotating the sleeve about theshaft until the ridge is resiliently displaced into said alignedgrooves.

According to a second feature of the invention there is provided anarrangement for setting a rotatable member relative to another rotatablemember, comprising a rotatable substantially cylindrical driving memberand a rotatable substantially cylindrical driven member, a firstplurality of regularly spaced axially extending grooves provided on abearing surface of the driving member, an axially extending ridgeprovided on a bearing surface of the driven member engageable with aselectable one of the grooves of the driving member, a substantiallycylindrical member, drivable by the driven member, a second plurality ofregularly spaced axially aligned grooves provided on a bearing surfaceof the drivable member, the number of the first plurality of groovesdiffering from the number of the second plurality of grooves, whereinfor setting the angular position of the driving member relative to thedrivable member the ridge of the driven member is inserted into alignedgrooves on the driving and drivable members.

The bearing surface of the driven member may be formed by its outerperipheral surface, and the bearing surfaces of the driving and drivablemember may be formed by their inner peripheral surfaces.

Advantageously, the ridge on the driven member is formed from a strip ofresilient material extending from a slot or recess in the wall of thedriven member so that the ridge is engaged by the aligned grooves ofthedriving and drivable mem bers after rotating the driven member untilthe ridge is resiliently urged into said aligned grooves.

Preferably, the wall of the driven member is provided at one end with apair of diametrically opposed recesses by means of which the drivenmember can be rotated to align said ridge with the aligned grooves ofthe driving and drivable members.

Preferably, the driven member is provided with an axially extending slotalong the length of its wall, the slot being diametrically opposite theridge. Advantageously, the number of said first plurality of groovesdiffers from the number of the second plurality of grooves by one.

The driving member may be keyed to a rotatable shaft.

Preferably, the drivable member is provided at one end with a pair ofdiametrically opposed recesses by means of which the angular position ofthe drivable member relative to the driving member can be determinedprior to the setting of said angular position by insertion of saidridge.

The first and second pluralities of axially extending grooves may extendfrom radial end faces on the driving and drivable member which arearranged to abut one another.

Preferably, said first and second pluralities of grooves extend alonglimited bore portions of the driving and drivable members which haveequal diameter.

The invention also includes a micrometer provided with such anarrangement.

DESCRIPTION OF THE DRAWINGS The aforegoing and further aspects of theinvention will now be described with reference to the accompanyingdrawings which show an arrangement of the invention applied to a digitalmicrometer. In the drawings:

FIG. 1 shows a side view of a micrometer partly in section;

FIG. 2 shows a perspective somewhat diagrammatical view of a componentof the micrometer of FIG. 1;

FIG. 3 shows a section on the line III-III of FIG. 1; and

FIG. 4 shows a section on the line lV-IV of FIG. 1, some parts beingomitted in FIGS. 3 and 4.

DETAILED DESCRIPTION OF THE EMBODIMENT The micrometer illustrated inFIG. 1 comprises a counter unit C incorporated in an anvil A and coupledby an assembly unit D to an operating spindle or shaft 3.

The counter unit C is required to register a zero reading when themeasurement face F of the spindle 3 is set to contact the measurementface F of the anvil in known manner.

The assembly unit D which will be described hereinafter facilitates theassembly of the micrometer in a manner which allows the counter unit Cto be set to register a zero reading when the measurement face F of theshaft 3 contacts the measurement face F of the anvil A, simply andaccurately.

The counter unit C comprises a plurality of rotatable number wheelsgenerally designated 1 which are coupled, for example, by pinnions (notshown) in the manner of known digital counters. The counter unit C isdriven through a unit wheel 2 which provides a bearing surface 12 aboutwhich the other number wheels rotate.

The assembly unit D couples the shaft 3 to the unit wheel 2 in a mannersuch that the counter unit C gives a digital indication of theseparation between the faces F l and F The assembly unit D includes theshaft 3, a driving member 4, a driven member 7 and a drivable memberconsisting of the unit wheel 2. The spindle 3 which extends through thecounter unit C, is manually rotatable to adjust the separation betweenthe faces F and F in known manner, as is indicated by the screw thread13.

The driving member 4 whichsurrounds a part of the shaft 3 comprises anannular member which is substantially cylindrical and has an axiallyextending bore 16. The driving member 4 is keyed to the shaft 3 by meansof a keylike projection 14 sliding in an axially extending slot 17 onthe outer periphery of the shaft 3 during adjustment of the separationbetween the faces F and F A bore portion 15 remote from the key 14 is ofsuch diameter relative to the diameter of the shaft adjacent thereto toallow a clearance between the outer periphery of the shaft 3 and theinner periphery of the annular member 4. The bore portion 15 is providedwith regularly spaced axially extending grooves (FIG. 3).

The unit wheel 2 comprising the drivable member of the assembly unit Dis formed by a second annular member which is substantially cylindricaland has an axially extending bore 18 coaxial with the shaft 3. Referringto FIG. 1 the bore of unit wheel 2 has a portion 19 of increaseddiameter which surrounds in part the driving member 4. A further portion20 of the bore of the unit wheel 2 is provided with regularly spacedaxially extending grooves 11 (FIG. 4). A clearance between the innerperiphery of the unit wheel 2 and the circumference of the shaft 3allows sleeve 7 to be inserted between the driving member 4 and theshaft 3. The sleeve 7 is provided at its outer periphery with an axiallyextending ridge 6 (FlG. 2). The ridge 6 is engageable with the grooves 5in the driving member 4 and with the grooves 1 1 in the unit wheel 2. Atone end of the sleeve 7, diametrically opposed recesses 8 are providedin the wall of the sleeve 7 by means of which a suitable tool can engagethe sleeve 7 to rotate the same about the shaft 3. The ridge 6 isprovided by means of an axially extending strip stamped out of the wallforming the sleeve 7 and severed at one end so that the ridge isresiliently depressible into the slot 21 from which the strip extends.The wall of the sleeve 7 is provided with an axially extending slit 22diametrically opposite the ridge 6 which allows slight deformation ofthe sleeve. The bore portion of the driving member 4 extends a limiteddistance along the bore 16 from a radial end face 23. Likewise, the boreportion 20 of the drivable member 2 extends a limited distance along thebore 18 from a radial end face 24. The radial end faces 23 and 24 arearranged to abut one another and the bore portions 15 and 20 are ofequal diameter. The number of the grooves 11 differs from the number ofgrooves 5 by one. A pair of diametrically opposed recesses 25 areprovided at the end of the drivable member 2 by means of which thedrivable member may be rotated.

The operation of the assembly unit during setting of the micrometer isas follows:

The micrometer is arranged with the driven member or sleeve 7 sodisplaced (to the left in FIG. 1) that the drivable member or unit wheel2 and the driving member 4 are displaceable relative to one another. Themicrometer is set to its initial position, in which the faces F 1 and Fare in contact, by rotation of the operating spindle or shaft 3. Sincethe driving member 4 is keyed to the shaft 3 its angular position isfixed. By means of a suitable tool engaging the recesses 25 thereof, theunit wheel or drivable member 2 is set so that the counter unit readszero, determining the angular position of the drivable member 2 relativeto the driving member 4 prior to the setting of this position by thedriven member 7. By means of a second tool which engages the recesses 8,the sleeve 7 is displaced to the right in FIG. 1, along the shaft 3 tothe axial position shown. At this stage, because the clearance betweenthe bore of the drivable member 2 and the shaft 3 is limited, the ridge6, is depressed into the slit 21. Owing to the difference in numberbetween the grooves 11 and the grooves 5, only one of the grooves 11 andone of the grooves 5, are aligned. By rotation of the driven member orsleeve 7, the ridge 6 is aligned with the aligned grooves which enablesthe ridge 6 to be resiliently urged out of the slit 21 into the alignedones of the grooves 1 1 and 5. Thereby, the driving member 4 is coupledto the driven member 7, which in turn couples the driven member to thedrivable member or unit wheel 2.

It will be appreciated that owing to the fact that the number of grooves1 1 and the grooves 5 differ by one,.a kind of Vernier effect isobtained so that for any angular position of the drivable member 2'relative to the driving member 4, the coupling between them can be setaccurately by the ridge 6.

I claim:

1. A device including means for setting a first rotatable memberrelatiye to a second rotatable member comprising,

a shaft providing said first rotatable member,

a first annular member having a first axially extending bore androtatable with said shaft,

at least a portion of the first axially extending bore being of suchdiameter relative to the diameter of the shaft adjacent thereto to allowa clearance between the shaft and the first annular member along saidportion of the bore,

a first plurality of grooves regularly spaced around the periphery ofsaid bore portion,

a second annular member having a second axially extending bore providingsaid second rotatable member and arranged to be coaxial with said shaft,

the diameter of said second axially extending bore allowing clearancealong the entire length of said second bore between the second annularmember and the shaft,

a second plurality of grooves different in number from said firstplurality of grooves being regularly spaced around the periphery of saidsecond bore,

a sleeve fitting and displaceable along said shaft, a ridge on the outerperiphery said sleeve engageable with aligned ones of said first andsecond plurality of grooves,

whereby the relative angular setting of the second rotatable memberrelative to the first rotatable member may be effected by aligning afirst groove in the first annular member with a second groove in thesecond annular member and locating the ridge of said sleeve member insaid aligned grooves.

2. A device as defined in claim 1, wherein the ridge on said sleeve isformed by a resilient strip extending from the wall of the sleevewhereby the ridge is located in the aligned first and second grooves byrotating the sleeve about the shaft until the ridge is resilientlydisplaced into said aligned grooves.

1. A device including means for setting a first rotatable memberrelative to a second rotatable member comprising, a shaft providing saidfirst rotatable member, a first annular member having a first axiallyextending bore and rotatable with said shaft, at least a portion of thefirst axially extending bore being of such diameter relative to thediameter of the shaft adjacent thereto to allow a clearance between theshaft and the first annular member along said portion of the bore, afirst plurality of grooves regularly spaced around the periphery of saidbore portion, a second annular member having a second axially extendingbore providing said second rotatable member and arranged to be coaxialwith said shaft, the diameter of said second axially extending boreallowing clearance along the entire length of said second bore betweenthe second annular member and the shaft, a second plurality of groovesdifferent in number from said first plurality of grooves being regularlyspaced around the periphery of said second bore, a sleeve fitting anddisplaceable along said shaft, a ridge on the outer periphery saidsleeve engageable with aligned ones of said first and second pluralityof grooves, whereby the relative angular setting of the second rotatablemember relative to the first rotatable member may be effected byaligning a first groove in the first annular member with a second groovein the second annular member and locating the ridge of said sleevemember in said aligned grooves.
 2. A device as defined in claim 1,wherein the ridge on said sleeve is formed by a resilient stripextending from the wall of the sleeve whereby the ridge is located inthe aligned first and second grooves by rotating the sleeve about theshaft until the ridge is resiliently displaced into said alignedgrooves.